1. Field of the Invention
The present invention relates generally to means by which material is separated or assorted according to size or dimensions of components by presentation to a series of openings or passages through which the components having dimensions below those of the openings or passages pass while those having dimensions greater than those of the passages or openings do not pass through. More specifically, the present invention relates to screen assemblies used in vibratory separators.
2. Description of Related Art
Vibratory screen separators with replaceable screen assemblies have long been known, and include a base, a resiliently mounted housing, a vibratory drive connected to the housing, and screen assemblies positioned on the housing. The screen assemblies are periodically replaced when process conditions dictate or when the performance of the screening media degrades due to abrasion, failure, or blinding. The screening media can be flat or pleated, single or multi-layered, laminated or un-laminated. Screen assemblies include screening media bonded to components structural in nature that are used to fasten or tension the screening media to a vibratory separator so that the motion of the separator is imparted to the screening media.
Flexible rectangular screen assemblies constructed by using structural components that form a “J” or similar shape on two sides of screen are known as hookstrip style screens. Hookstrip style screens are fastened to vibratory separators by pulling the screen assembly taut over a crowned deck. The “crown” or “radius” in the deck is necessary because the geometry of the crown keeps the flexible screen in contact with the vibrating deck without approaching tension levels that would damage the screening media.
Screen assemblies constructed by bonding screening media to rectangular structural frames that minimize the flexibility of the screen assembly are known as panel style screens. The structural frame may or may not have internal supporting cross members. Panel style screens are fastened to vibratory separators by clamping one or more surfaces of the structural frame to a mating surface (or deck) of the vibratory separator. The decks of vibratory separators that accept panel screens are noticeably less crowned than the decks of vibratory separators that accept hookstrip style screens, but the decks are usually slightly crowned to prevent panel style screens from flexing or chattering when the vibratory separator is in motion.